The present invention relates to a method and apparatus for die forming elongate strips of material capable of undergoing plastic deformation, and more particularly to a method and apparatus for intermittently die-forming successive segments of an elongate strip of such material into a continuous, formed strip of finite length.
Flat strips or ribbons of material have been formed into corrugated strips by feeding the ribbon through gear-like, mating dies, or by positioning the ribbons between elongate dies having a length substantially equal to or greater than the length of the corrugated strip being produced. Although these prior art methods can be used to produce corrugated strips having a cell shaped structure suitable for use in manufacturing structural, honeycomb cores, these methods do not produce a formed strip with the precision and accuracy required for use in compounding cores suitable for applications in the aerospace industry.
Moreover, it is desirable to compound honeycomb cores for use in the aerospace industry using newly automated techniques of projection welding. If projection welding is to be used, a projection must be formed on the nodes of the corrugated strip at very precise locations. The height and spacing of these projections must be very precisely and accurately formed in order to utilize the automated techniques. The prior art methods and apparatus for producing such corrugated strips are not sufficiently accurate to produce a uniform strip with precisely formed nodular projections.
A broad object of the present invention is to provide methods and apparatus for pressure forming elongate, narrow ribbons composed of material capable of undergoing plastic deformation into predetermined shapes. Another object of the present invention is to provide methods and apparatus for die forming successive segments of an elongate ribbon into a continuous ribbon having a repetitive formed configuration. Another object of the present invention is to provide methods and apparatus for forming metal ribbons into a corrugated shape adequate for use in compounding honeycomb cores. Another object of the present invention is to provide methods and apparatus for forming metal ribbons into a corrugated shape with precisely defined and accurately located projections at the nodes of the corrugated strips.